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Biomedical subjects

Y C Huang

Publications and source records attributed to Y C Huang.

At least 91 records · Page 5Linked to original sources
PubMed1999

Eugenodilol: a third-generation beta-adrenoceptor blocker, derived from eugenol, with alpha-adrenoceptor blocking and beta2-adrenoceptor agonist-associated vasorelaxant activities.

Eugenodilol, derived from natural eugenol, was first investigated with in vivo and in vitro models. In our in vivo study, eugenodilol (0.5, 1.0, and 1.5 mg/kg, i.v.) produced dose-dependent hypotensive and bradycardic responses in pentobarbital-anesthetized Wistar rats. Eugenodilol also inhibited the tachycardia and arterial pressor effects induced by (-)isoproterenol and phenylephrine, respectively. In our in vitro study, eugenodilol competitively antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects and tracheal-relaxation responses on isolated guinea pig tissues in a concentration-dependent manner. The apparent pA2 values were 7.88+/-0.12 for right atria, 7.52+/-0.05 for left atria, and 7.33+/-0.15 for trachea, indicating that eugenodilol was a nonselective beta-adrenoceptor blocker. In thoracic aorta experiments, the apparent pA2 values of alpha-adrenoceptor blockade were 7.05+/-0.25 and 6.87+/-0.08 for eugenodilol and labetalol, respectively. In addition, eugenodilol produced cumulative relaxation responses on isolated guinea pig tracheal strips. The effects were competitively antagonized by ICI 118,551 (10(-8)-10(-6) M), a relatively selective beta2-adrenoceptor antagonist. In the radioligand-binding assay, the Ki values of [3H]CGP-12177 binding to rat ventricle and lung membranes were 9.72 and 48.29 nM, respectively, and the value of [3H]prazosin binding to rat brain membrane was 38.72 nM. These results further confirmed the alpha/beta-adrenoceptors-blocking activities of eugenodilol reported in the functional studies. We conclude that eugenodilol is a novel third-generation beta-adrenoceptor blocker with ancillary blocking activity at alpha-adrenoceptors and weak sympathomimetic activity at beta2-adrenoceptors.

Adrenergic beta-Agonists↗
PubMed1999

Comparison of enterovirus 71 and coxsackie-virus A16 clinical illnesses during the Taiwan enterovirus epidemic, 1998.

OBJECTIVES: To compare enterovirus 71 (EV 71) with coxsackievirus A16 (Cox A16) clinical illness in patients at Chang Gung Children's Hospital during Taiwan's enterovirus epidemic of 1998. METHODS: With the use of the immunofluorescence assay and neutralization test, 177 cases of EV 71 and 64 cases of Cox A16 illness were confirmed from April to September, 1998. The clinical signs and symptoms, complications and case fatality rates were compared. RESULTS: Three-fourths of the cases were younger than 3 years of age, and the ratio of males to females was 1.3 in the EV 71 group and 1.2 in the Cox A16 group. In the EV 71 group 120 (68%) cases were uncomplicated, including 94 cases of hand, foot and mouth disease and 15 cases of herpangina, and 57 (32%) cases had complications, including 13 (7.3%) cases of aseptic meningitis, 18 (10%) cases of encephalitis, 4 (2.3%) cases of polio-like syndrome, 8 (4.5%) cases of encephalomyelitis and 12 (6.8%) cases of fatal pulmonary edema. Fourteen (7.9%) patients died, including 12 cases of pulmonary edema and 2 cases of encephalitis; seven (4%) patients had sequelae. By contrast, 60 (94%) of the 64 cases of Cox A16 infection were uncomplicated and only 4 (6.3%) cases were complicated by aseptic meningitis; no fatalities or sequelae were observed. By multivariate analysis vomiting (P = 0.01) and fever higher than 39 degrees C plus lasting longer than 3 days (P = 0.02) were significantly more frequent in the EV 71 group. CONCLUSION: EV 71 illness is more severe with significantly greater frequency of serious complications and fatality than is illness caused by Cox A16.

Adolescent↗
PubMed1999

Isoeugenolol: a selective beta1-adrenergic antagonist with tracheal and vascular smooth muscle relaxant properties.

Isoeugenolol (1.0, 3.0, 5.0 mg/kg, i.v.) produced a dose-dependent bradycardia and a decrease in blood pressure in anesthetized Wistar rats. Isoeugenolol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by (-)phenylephrine. In isolated guinea pig tissues, isoeugenolol antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects on the atria and tracheal relaxations in a concentration-dependent manner. The apparent pA2 values for isoeugenolol on right atria, left atria and trachea were 7.63+/-0.03, 7.89+/-0.12 and 6.12+/-0.05, respectively, indicating that isoeugenolol was a highly selective beta1-adrenoceptor blocker. On the other hand, isoeugenolol produced a mild direct cardiac depression at high concentration and was without intrinsic sympathomimetic activity (ISA). In isolated rat thoracic aorta, isoeugenolol relaxed more potently the contractions induced by (-)phenylephrine (10 microM) and 5-HT (10 microM) than those by high K+ (75 mM). In isolated guinea pig trachea, isoeugenolol attenuated the carbachol (1 microM)-con-tracted trachea more significantly than those contracted with high K+. Furthermore, the binding characteristics of isoeugenolol and various beta-adrenoceptor antagonists were evaluated in [3H]CGP-12177 binding to rat ventricle, lung and interscapular brown adipose tissue (IBAT) membranes. The -log IC50 values of isoeugenolol for predominate beta1-, beta2- and beta3-adrenergic receptor sites were 5.82+/-0.09, 4.74+/-0.05 and 4.73+/-0.12, respectively. In conclusion, isoeugenolol was found to be a highly selective beta1-adrenoceptor antagonist with tracheal and vascular smooth muscle relaxant activities, but was devoid of alpha-adrenoceptor-blocking action.

Adrenergic beta-1 Receptor Antagonists↗
PubMed1999

Color Doppler ultrasonographic evaluation of osteomyelitis in children.

We investigated the capability of color Doppler sonography in evaluating acute osteomyelitis in children. Twelve children suspected of having osteomyelitis were evaluated with color Doppler ultrasonography at admission and at regular intervals to observe the inflammatory process of osteomyelitis, determine the response of antibiotic therapy, and predict the need of surgery in these patients. At admission, color Doppler flow within or around the infected periosteum was found in patients with symptoms for 4 days or longer, whereas those with symptoms for less than 4 days showed no color Doppler flow within and around the periosteum. During sonographic follow-up, six cases were found to have increased color Doppler vascular flow within and around the affected periosteum, and two of them had periosteal abscess. They eventually required surgical treatment. Persistent or increased color Doppler flow during follow-up examination correlated with elevated serum levels of C-reactive protein as well. Our study indicated that color Doppler vascular flow within or around the infected periosteum correlated with advanced acute osteomyelitis, and surgery usually was required in these patients. Those with early stage acute osteomyelitis usually showed no vascular flow within or around the infected periosteum. Thus, color Doppler sonography allowed detection of advanced osteomyelitis and revealed the progression of inflammation during antibiotic therapy. Color Doppler ultrasonography might be valuable in determining the efficacy of antibiotic therapy and justifying the need for operation.

Acute Disease↗
PubMed1999

Pharmacokinetics, tissue distribution and photodynamic therapy efficacy of liposomal-delivered hypocrellin A, a potential photosensitizer for tumor therapy.

Hypocrellin A, from Hypocrella bambusae, is a novel photosensitizer of high singlet oxygen quantum yield for photodynamic therapy (PDT). Tissue distributions were studied in tumor-bearing mice as a function of time following administration. The tumor model was S-180 sarcoma transplanted into one hind leg of male Kunming mice; hypocrellin A (HA) was delivered to the mice by intravenous injection of 5 mg/kg of body weight as a suspension either as a unilamellar liposome or in dimethyl sulfoxide (DMSO)-solubilized saline. The HA was isolated from several tissues and organs, as well as tumors and peritumoral muscles and skin. Quantitation was performed by a high-performance liquid chromatographic technique with detection that utilizes the native fluorescence of HA. Independent of the delivery system, the dye was retained in tumors at higher concentrations than in normal tissues, except for kidney, liver, lung and spleen. The dye retention in tumors was high and was vehicle dependent. For the liposomal system, the maximal accumulation in tumor and maximal ratios of dye in tumor versus peritumoral muscle and skin occurred 12 h postinjection; for the DMSO saline system, the maximal ratio occurred earlier, 6 h postadministration. Liposomal delivery improved the selective accumulation of the dye in tumor with higher maximal levels in tumor and higher ratios of tumor-to-muscle and tumor-to-skin. Levels of dye were very low or not detectable in the brain. The PDT efficacy of HA in the liposome and DMSO saline systems was determined by evaluating the tumor volume regression percent. The PDT efficacy of HA in liposomes was highest when light treatment was performed at 12 h postinjection, consistent with the highest retention of HA in tumors. Similarly, the maximal PDT efficacy in DMSO saline was attained at 6 h postinjection, the highest HA retention point in tumor. Moreover, the peak PDT efficacy of HA in liposomes was much higher than that of HA in DMSO saline and even hematoporphyrin monomethylether.

Animals↗
PubMed1999

Non-typhoid Salmonella subdural empyema in children: report of two cases.

Subdural empyema caused by Salmonella in childhood is an uncommon condition. The predisposing factors for this condition are not clearly established, especially in young children. Here we present two cases of subdural empyema caused by non-typhoidal Salmonella. Both of the patients suffered prolonged fever without local signs of infection on admission. Subdural empyema was subsequently detected by brain echo and brain computerized tomography (CT) scan in both cases. Cerebrospinal fluid (CSF) study was not done in case one due to prominent mass effect on brain CT; in case two the CSF analysis showed pleocytosis, but CSF bacterial culture was negative. Neither enteritis nor obvious meningeal sign was noted. Both cases responded well to surgical drainage and systemic antibiotics treatment.

Child, Preschool↗
PubMed1998

Identification of the subunit and important target peptides of pig heart NAD-dependent isocitrate dehydrogenase modified by the affinity label adenosine 5'-O-[S-(4-bromo-2, 3-dioxobutyl)thiophosphate].

Pig heart NAD-dependent isocitrate dehydrogenase is inactivated by adenosine 5'-O-[S-(4-bromo-2,3-dioxobutyl)thiophosphate] (AMPS-BDB) with incorporation of 1.78 mol of reagent/mol of average subunit. Complete protection against the inactivation is provided by 20 mM isocitrate + 1 mM Mn2+, and the incorporation is decreased to about 1.3 mol of reagent/mol of average subunit. The addition of NAD, NADH, or Mn2+ alone has little effect on the functional changes produced by AMPS-BDB, while ADP gives only partial protection against the inactivation. The ability of ADP to decrease the Km for isocitrate is not affected by the AMPS-BDB modification of the enzyme. These results indicate that the isocitrate substrate site is the target of AMPS-BDB. The enzyme has three types of subunits with a tetramer having the composition alpha2 beta gamma. Here, [2-3H]AMPS-BDB-modified subunits are separated by HPLC on a C4 reverse-phase column, after the treatment of the modified enzyme with 4 M urea. The predominant radioactivity is distributed in alpha and gamma subunits. However, evidence based on recombination of subunits from modified and unmodified enzymes indicates that only labeling of the alpha subunit is responsible for inactivation by AMPS-BDB. Subsequently, the separated modified subunits were chemically cleaved by CNBr and then purified by HPLC using a C18 column. The labeled peptides were further digested by pepsin, purified by HPLC, and sequenced. These results indicate that R88 and R98 from the alpha subunit are the major targets of AMPS-BDB which cause inactivation and that these are at or near the isocitrate site of the enzyme.

Adenosine Diphosphate↗
PubMed1998

Cardiokymograph system with a capacitance transducer and its preliminary application in the measurement of heart wall movement.

A novel cardiokymograph system is introduced. The new system features a capacitance transducer with increased sensitivity and can be used in multichannel measurements. The novelty of this technique is the injection of a current into the patient coupled with the use of a capacitive displacement transducer and the possibility of multichannel monitoring. It provides for the possibility of removing breath noise when some signal processing technique, such as adaptive filtering, is used. Further investigation is needed to demonstrate clinical significance and pathologies.

Adult↗
PubMed1998

Yeast carriage on hands of hospital personnel working in intensive care units.

The frequency and distribution of yeast carriage on the hands of hospital personnel working in intensive care unit (ICUs), was investigated. Hand carriage of yeast and Candida species was 46 and 29%, respectively. Rhodotorula sp. and Candida parapsilosis were most frequently recovered. There was no significant difference in frequency or distribution of yeasts and Candida sp. recovered among the three ICUs. Seventeen C. parapsilosis isolates and three Candida albicans isolates were genotyped by electrophoretic karyotyping using contour-clamped homogenous electric-field gel electrophoresis. Eleven separate types of C. parapsilosis and two types of C. albicans were identified. There was no common genotype among these isolates, even within the same unit. We conclude that yeast carriage on the hands of personnel working in ICU is common, but these yeasts are usually not acquired from a common source in the ICU.

Candida↗
PubMed1998

Lactobacillus kunkeei sp. nov.: a spoilage organism associated with grape juice fermentations.

A Gram-positive rod was isolated from a commercial grape wine undergoing a sluggish/stuck alcoholic fermentation. The organism produced L-lactic acid from glucose, possessed weak catalase activity, and fermented relatively few carbohydrates, i.e. glucose, fructose, sucrose, raffinose (weakly) and mannitol. The 16S rRNA gene sequence analysis revealed that the isolate was phylogenetically a member of the genus Lactobacillus and formed a distinct subline within the Lact. casei cluster of species. Based on phenotypic and phylogenetic evidence, a new species is proposed, Lact. kunkeei. The type strain of Lact. kunkeei is ATCC 700308.

DNA, Bacterial↗
PubMed1998

Antimicrobial susceptibilities of Campylobacter jejuni and coli by using E-test in Taiwan.

To report the in vitro antibiotic susceptibility of Campylobacter species, we determined the MICs of 6 antibiotics by E-test for 93 human clinical strains and 35 chicken strains. The 6 antimicrobial agents tested were gentamicin, erythromycin, clindamycin, tetracycline, ciprofloxacin, and nalidixic acid. Isolates from humans were significantly more susceptible than chicken strains to erythromycin, clindamycin and ciprofloxacin. Nearly all of the human and chicken strains were susceptible to gentamicin. Among human isolates of C. jejuni, cross-resistance between nalidixic acid and ciprofloxacin was found in 66% of the strains, but none of the nalidixic acid-susceptible strains was resistant to ciprofloxacin. The higher prevalence of ciprofloxacin resistance in this area may be attributable to the large amount use of quinolones in poultry. Because of the high resistance rates of chicken isolates to the commonly used antimicrobial agents, it is necessary to create innovative methods to limit the inappropriate use of antibiotics in poultry in order to prevent the spread of the drug-resistant strains to humans.

Animals↗
PubMed1998

Outbreak of Candida albicans fungaemia in a neonatal intensive care unit.

During a 4-month period, 9 premature infants hospitalized in a neonatal intensive care unit (NICU) developed Candida albicans fungaemia. All 9 infants received antifungal agents. Fluconazole was administered in 7 patients and successfully eradicated this organism in 6 with no adverse effects. For epidemiological investigation, 64 environmental specimens and hand-washings of all 54 staff members involved in the NICU were examined for the presence of this organism. No C. albicans could be identified from environmental sources, while the hand-washing of 1 nurse was C. albicans-positive. Two genotyping methods, including electrophoretic karyotyping using contour-clamped homogeneous electric field gel electrophoresis and polymerase chain reaction-based direct sequencing of rRNA gene, were used in the analysis of the isolates recovered from blood cultures of the infants, the hand-washing of the nurse and 7 control isolates. Both methods yielded comparable results and revealed that all 13 isolates from infected infants as well as the isolate from hand washing of the nurse were of the same genotype while the control isolates were distinct. These results suggest that the outbreak of C. albicans fungaemia was caused by a particular strain and possibly via cross-infection. In addition, we showed that fluconazole seemed to be safe and effective in treating C. albicans fungaemia in neonates, although the data were limited.

Antifungal Agents↗
PubMed1998

Multiple-objective optimal designs.

We present illustrative multiple-objective optimal designs for nonlinear models useful in biomedical studies. The aim is to demonstrate the added benefits of using a multiple-objective design over the traditional single-objective design.

Chemistry, Pharmaceutical↗
PubMed1998

Vitamin B-6 requirement and status assessment of young women fed a high-protein diet with various levels of vitamin B-6.

The vitamin B-6 requirement of young women consuming a constant high-protein diet (1.55 g/kg body wt) and the effect of various ratios of vitamin B-6 to protein on this requirement were studied. Eight women were fed a lactoovovegetarian basal diet containing 0.45 mg vitamin B-6 (2.66 micromol as pyridoxine) and 30 micromol carnitine for 92 d. The protocol consisted of successive baseline adjustment (9 d), depletion (27 d), and repletion (two 21-d and then one 14-d) periods. Vitamin B-6 intakes were 1.60, 0.45, 1.26, 1.66, and 2.06 mg, resulting in ratios of vitamin B-6 (in mg) to protein (in g) for the five periods of 0.016, 0.005, 0.013, 0.017, and 0.021, respectively. Direct and indirect as well as short- and long-term vitamin B-6 status measures were assessed weekly. Regression analysis revealed that the amount of dietary vitamin B-6 required to normalize urinary 4-pyridoxic acid, plasma pyridoxal-P, erythrocyte pyridoxal-P and pyridoxal, and erythrocyte alanine and aspartate aminotransferase activity coefficients to predepletion baseline values was 1.94 mg vitamin B-6/d (0.019 mg vitamin B-6/g protein). This study suggests that the current vitamin B-6 recommended dietary allowance of 1.6 mg/d based on 0.016 mg/g protein is not an adequate intake and may require reevaluation.

Adult↗